Pot type oil burner pilot and igniter



Aug. 10, 1954 P. B REVARD 2,685,920

POT TYPE OIL BURNER PILOT AND IGNITER Filed Sept. 25, 1950 2 Sheets-$heet 1 PROC TEE BRE VARD 3nnemor 8., gw zw P. BREVARD POT TYPE OIL BURNER PILOT AND IGNITER Aug. 10, 1954 2 Sheets-Sheet 2 Filed Sept. 25, 1950 PROCTER BRE'VARD 3nuentor Patented Aug. 10, 1954 UNITED STATES PATENT OFFICE 9 Claims.

pot type of burner, the oil flows by way of a supply pipe into an oil pot or reservoir at the bottom of the burner where it forms a pool from which it is vaporized for burning. Most such burners have an oil reservoir, usually circular, with a somewhat concave bottom so that the area of oil exposed for burning is greater the greater the amount of oil in the reservoir, the rate of burning being regulated by regulating the rate of flow of oil to the reservoir. When oil is caused to enter the-reservoir only slowly, the pool of oil is relatively small and only a relatively small flame is produced. When, on the other hand, oil is caused to enter the reservoir more rapidly, the oil forms a larger pool and a larger flame is produced. The sides of the burner above the highest level attained by the oil are generally perforated and otherwise formed to permit air to be drawn into the rising column of hot gases and thus to promote better and more complete combustion of the oil vapors. Heating and vaporization of fresh oil flowing into the reservoir when the burner is in operation, is caused by a combination of radiant heat from the burning vapors in the upper part of or above the burner and by conduction of heat through the metal parts of the burner from the region of burning to the walls and bottom of the reservo1r. I

The conventionalpot type of burner, such as that just described, has several serious disadvantages, one of which is the difliculty of gen-,

erating a flame in the burner when it is coldso that the oil will continue to burn. The usual method for generating or starting the burner is to open the valve in the oil supply pipe suificiently to produce a pool of oil of more or less extent in the reservoir and then to ignite it by placing burning paper or other combustible kindling material in the pool of oil. Inasmuch as the oil generally used in such stoves often has an' ignition or fire temperature considerably higher than ordinary room temperature, and since it is in contact with .a relatively large mass of cold metal, it is necessary to generate considerableheat within the burner before the oil and the various metal parts'of'the burner become hot enough for the combustion of the oil to'proceed and the burner to begin to operate.

Not only is the procedure described unhandy, inconvenient and time consuming, often requiring from 10 to 30 minutes to generate even a small burner, but there is generally no way of removing the ash and residues left by the kindling material without first shutting off .the burner entirely and allowing it to cool. The kindling material is generally not burned completely but remains as an oil-soaked, carbonaceous mass in the bottom of the burner. Prolonged heating of the oil trapped in the mass promotes carbonization of the oil and eventually the stove must be shut down and the carbonaceous residues removed. I

An additional and important disadvantage of the conventional type of pot burner is that when the burner is on pilot an undesirably large pool of oil must be maintained in the bottom of the reservoir to keep the entire burner warm and to insure a continuous flame which will not become extinguished. This leads to an undesirably high rate of consumption of oil during those periods when the burner is not required to furnish heat but when it is on pilot. The accumulation of residues, such as those mentioned above, in the reservoir of the pot increases the rate of its oil consumption when on pilot. These effects are all highly undesirable.

It is, therefore, an object of the present invention to provide apparatus for overcoming the disadvantages inherent in heretofore known procedures for igniting oil in a pot type oil burner and for reducing the rate of oil consumption by the burner when on pilot.

An additional object is to provide unitary apparatus securable to a pot type oil burner whereby oil in the burner can be ignited readily and'conveniently and. whereby a small but hot pilot flame is maintained continuously when the burner is on pilot.

An additional object is to provide apparatus whereby oil in a pot type oil burner can be. ignited quickly and the generating period shortened greatly.

Anadditional object is to provide a pilot flame chamber securable to a pot type oil burner in which a continuous pilot flame can be main-.

tained without the necessity of heating the entire burner, and with a reduction in the rate of oil consumption when the burner is on pilot.

Other objects will be apparent as the description proceeds.

The apparatus of the invention can be best 3 understood by reference to the accompanying drawing wherein, in the interest of clarity, certain features are shown on a somewhat exaggerated scale and wherein:

Figure 1 is a side elevation, partially in section, of a pot type oil burner equipped with a pilot and igniter apparatus embodying features of the invention;

Figure 2 is afragmentary side sectional elevation of the burner and: apparatus of Figure 1 rotated through 180 degrees in a horizontal plane;

Figure 3 is a sectional elevation taken along the line IIIIII of Figure 2.

Figure 4 is a fragmentary side sectional elevation of a pot type oil burner equipped'with a pilot and igniter apparatus sembodyingvzanothen modification of the invention;

Figure 5 is a sectional. elevation taken along Figure 7 is asectional elevation takenalon'g' the line VII-VII of Figure 4.

Referring now to the drawing, a-conventional pot type oil burner H, which may becircular in design as-in Figure l'but which can be of any other suitable shape, is provided near thebottom thereof witha somewhat elongated horizontal tube 12; herein sometimes referred-touts a pilot tube, the inner endof which is secured, as by welding'at E3 or otherwise, in air tight/relationship on the side of the-reservoir=of the burner and in-communication with the interiorthereof; The reservoir of the burner is preferably-pip vided with a channel [4; thebottom" of which-is substantially level with the lowest point in the reservoir and with the lower inside surface of the tube H! to provide for free flow of oil i9 between the lowest point in thereservoir and in the tube. The pilot tube 12 is closedat "its outerend, i. e. at its'end farthest removedf-rom the burner, e. g. witha tube end *plate 21 as shown clearly inFigure 2 which can conveniently be welded inside the end of the'tube as at 28to provide an oil and air tightseal. The tube 12 is also provided with an igniting "p0rt'34' of *convenient size in its upper wall 'a'djacent'itsouter end and well above-the highest"level-attained by oil in the burner reservoir. A wick3-3 of suitable form and material can also be'provided and secured in a convenient wick holder'ZB. The

wick holder can be secured by welding "as "at 32, or otherwise, to'thc inner surfaceof the tube end plate 2'5 and can compriseahorizontal arm with a hole in it through which the "wick-canbe forced. The wick, conveniently a short'length' of cord or rope of difficultly combustible absorbent material, is preferably positioned in the wick holder with one of'its ends closelyedjacent' the igniting port (-34 in the tube 12 'andwit'h'its other endresti'ng' on the bottom of the tube I2 so that the wi'cl "willat alltimes be saturated.

is provided having 'an'internal diameter such.

that it fitssnuglyover the-outer end 'ofthepilot tube i2 but so that it can be rotated easily thereon. A circumferential slot 2! can be provided in the sleeve 25, together with a pin 24 which extends through the slot 2| and threadably engages or is otherwise secured to the pilot tube 12. The pin 24 prevents longitudinal movement of the sleeve 25 but permits it to be rotated through an angle which depends upon the length of the -slotil, usually throughat. least about degrees; A sleeve port 31 iis'providcd'inthe sleeve adapted to be in register with the igniting port 34 when the sleeve is rotated, e. g. to the limit of its travel in one direction. Access is thus provided to the' 'saturated upper end of the wick 33 so vthat oilthereon can be ignited easily and conveniently with a match when the sleeve 25 is suitablylrotatedx Dueto the natural draft downward through the ports 3! and 3 1 and inward through the tube l2 into the burner, the oil on the wick burns immediately with a downwardly drawn fierce flame which iscommunicated quikly to oil in the bottom of the pilot'tub'e il" and'thence-quickly to oil in the bottom of the oil reserv'oir' 'of' theburner. Assoonas oil "in the 'burneris burning freely, usually Wlthill'fi. few seconds, the sleeve 25 can be rotated -=to bring theport 31 out of register with "the port 34 to prevent further burningof oil irFthe-outer end ofthe-p'ilottube and to preserve 'thewic'k for subsequent use. end plate' z'fi 'can be omitted'i'f desired, its chief function being to *giVe 'th'eapparatus a better appearance and to provide a =l-znurled flange for rotating the sleeve:

pilot tube l 2 by way-'of an oilsupp'ly lined? -communicating' with'it, e. gs, through thebottom wall dfthe tube; suitably at-a pointnear the-inner end of therotatablesleeve 25.-

The pilot tube" i2 "is provided with transverse partitions l5- and' ls which may be-of any convenient construction, suitably a-pairof discs with turned up edges-which engage frictiona'lly the inner-surface of the tube wall. The discs can be assembledin thetube by forcing them into the 'tube for -adesi-re'd distance. They can be secured in place by weldingifdesired, but this is not always necessary. The inner partition 15, i. ei'the partitionnearestthe-burner; can bis-"located "as'near theinner end of the tube asconvenient. Although in the drawing the pilot tube-f2 is illustrated asextending through the wall of the burner reservoin-it' -'is apparent that it can abut 'andbe secured to the-outer surface ofthereservoirwall-and that the wall itself can serveas theinnerpartition. The other'or outer partition 16 is separated from the inner partition byasuitable distancaoften by a distance equal tonic-out one' or 'two'diameters of the pilot tube 12; and-is preferably 'locatedbetween the inner partition -and-the oil inlet line 22. -The chamber within the pilot tube "12 between the partitions E5 and if? is herein'sometimes referred to as-a pilot chamber.

Each-of thepartitions l5 andlfi"-is,"as'shcwn in detail in Figures 2 and 3, provided'adjacent' itsbottom' edge with'a partitionport, H and. 18, respectively, which mayhe'round cr'ofany other convenient shape and which'preferably extends between the'lower edge andapproximately the centerof the partition. A section of the. parti-. tion'between the partitionport and; the bottom wall of the;tube l2.'can.be .cut' away,.if. desired, ,to provide asmall channelfw to.a1low .oil to.,flow

It is apparent that "the-sleeve Other convenient means can be 'emp'loyed to open and close the igniting port 34, if desired. 'Oilis introduced into the longitudinallywithin the tube without restriction even when only a small quantity is present.

Airis admitted into the upper portion of the pilot-chamber above the highest level attainable by oil-therein to promote combustion of oil in the chamber. In one modification, shown particularly in Figures 1, 2 and 3, a number of air ports 41 are provided in the wall of the pilot tube 12 between the partitions i5 and [6. The airports are preferably formed, as shown especially in Figure 3, at an acute angle to the tangent to the tube wall in such fashion as to direct entering air downward and substantially tangential to the inner surface of the tube wall to promote turbulenceand swirling of the mixture of air and oil vapors in the pilot flame chamber. Due to the natural draft of the flue, air is drawn with appreciable force through the air ports 4| into the pilot chamber where it promotes combustion of oil therein, the flame issuing quietly into the burner through the port [1 in the inner partition l5.

The pilot tube 12 is generally of such a length that the sleeve 25 and the oil supply line 22 are located entirely outside the outer jacket of the furnace orstove to facilitate easy lighting of the oil through the igniting port 34 and also .to provide'easy access to the oil supply line throughout its entire length. The air supply for the air ports 4| is thus sometimes drawn from the stream circulating Within the jacket. In some instances, particularly where forced circulation of air through the jacket is employed, it may be desirable to draw air for the pilot chamber from outside the jacket. To accomplish this, the modification shown in Figures 4, 5, 6 and '7 can be employed with advantage. In the latter modification, air is .conducted from outside the outer jacket 42 of the stove by way of an air passageway, such as an air tube 36. The inner end of the air tube 36 can be closed or it can abut the outer surface of the inner partition, or pot wall, 15 to prevent the flow of excessive amounts of air from the inner end of the tube. The air tube 36 passes through the upper sections of the outer partition I6 and of the tube end plate 21 and can, if desired, be welded as at 31 to the latter to prevent its longitudinal movement. A sleeve end plate port, 35 of Figures 6 and 7, is provided in the sleeve end plate 26, in case the latter is present, which usually has a diameter somewhat greater than that'of the air tube 36 and which is preferably in register with the outer end of the latter at least when the tube port 34 is closed by rotating the sleeve 25. Suitable air ports 38, e. g. a row of small holes, are provided along the length of the section of the air tube 36 extending into the pilot chamber. The small ports 38 are preferably formed so that they direct air issuing through them from within the tube 35 tangentially downward along the inner wall surface of the pilot tube 12 and thus across the surface of oil lying in the bottom of the chamber. In this way, and due to the natural draft causing the flow Of air through the port 35, the air tube-36 and the air ports 38 into the pilot flame chamber and thence through the partition port I! into the body of the burner, a continuous swirling of air and burning oil vapors is maintained in the pilot chamber, the pilot flame generally issuing quietly from the port I! into the burner. 7

Due to the fact that the pilot chamber is small and its walls are continuously hot, adequate volatilization of even small amounts of oil lying in the chamber occurs thus enabling the burner to be kept on pilot with a minimum oil consumption and with substantially no collection of carbonaceous material or other residues in the pilot chamber or in the burner reservoir. Burners of average size can be kept on pilot with a consumption-of oil which rarely exceeds more than about 0.75 milliliter of oil per hour as compared with a consumption of about 2 milliliters per hour for the same size burner when the oil is fed directly into the oil reservoir of the burner. When the rate of oil supplied to the burner is increased, e. g. in response to the action of a thermostatic or manual control, the additional oil flows from the tube l2 along the channel l4 into the burner reservoir and combustion occurs therein, the burner reaching full heat rapidly.

It is apparent, also, that in instances where means for igniting oil in the burner or in the pilot chamber are not desired, the igniting port 34, the rotatable sleeve 25 and the wick 33 can be omitted. In certain of such instances the tube end plate 21 can serve as the outer partition, there being then no need for a port in the outer partition corresponding to the port I8 shown in Figure 4 since the oil inlet pipe 22 will, of course, conduct oil directly into the pilot chamber.

I claim:

1. In pilot apparatus for a pot type'oil burner, the combination including: a substantially horizontal pilot tube securable at its inner end to the reservoir of a pot type oil burner; a tube end plate closing the outer end of the tube; means to introduce oil into the pilot tube; inner and outer transverse partitions in the pilot tube defining a pilot chamber shorter than the pilot tube adjacent the inner end of the tube, the partitions each having a port adjacent to and extending to the bottom wall of the tube to permit unrestricted flow of air and of oil along the bottom wall of the pilot tube; and means to introduce air from outside the pilot tube into the pilot chamber above the level of oil therein.

2. Apparatus as claimed in claim 1 wherein the means for introducing oil into the pilot tube is located between the outer partition and the outer end of the tube.

3. Apparatus as claimed in claim 1 wherein the means to introduce air into the pilot chamber comprises a plurality of air ports in the wall of the pilot chamber adapted to direct air substantially tangential to the wall of the pilot tube.

4. Apparatus as claimed in claim 1 wherein the means for conducting air into the pilot chamber comprises an air tube extending through the outer partition and the tube end plate and having a plurality of air ports in its section extending into the pilot chamber adapted to direct air issuing therefrom substantially tangential to the wall of the pilot tube.

5. In pilot and igniting apparatus for a pot type oil burner, the combination including: a substantially horizontal tube closed at its outer end and securable at its inner end to the reservoir of a pot type oil burner; means to introduce oil into the pilot tube; a pair of transverse partitions in the tube defining a pilot chamber shorter than the pilot tube adjacent the inner end of the tube, the partitions each having a port adjacent to and extending to the bottom wall of the tube to permit unrestricted flow of air and of oil along the bottom wall of the pilot tube; an igniting port in the top of the tube wall adjacent its outer end; means to open and close the igniting port; and means separate from the igniting port to conduct air into the pilot chamber.

Biz-Apparatusr asaclaimed in;-clai-m-;-5 rincluding atwgiekjdisposect withinthe:pi lot-'tube-,- but without thee-pilot chamber; h one of -slpendeaaslja cehtzt-he: igniting:portwandrwith: its -.other: end in contact, With-the bottemrofathe-tu-bewall;

therreservoirx ,Of': 'a pot; type foil burner; A means 10;

to; introduce" voil-1;*imtoithe; 1101:: tube}: a, pain-10f transvense=;--p,artitionsd :ttheepi'lot tube idefinmgaaajpilotwhamber shorter than the -pilot tube-ad= jacent't hei vinner vendmf the .tubegv the; partitions eaehwhaviil vawpol to the abottomewailv 'of ath'e pilot; 'tubetato permit unrestricted flow .of na-ir:- ofroilwa-longy the bottom -wa-1l *tOfr the pi lot tube; an igniting per-t inZthe= tOpfiUff the p i'l0t= tubevwalladjacent: its:

outemend; amairwassage wayt-forr-,conveyne air: 20:-

fnomoutsidertheztube into therr'pi'loti chamber 5':

andfimeans tosopeng-andrcloseathedgnitingzportz.

f- 8nlnzpilot and: ignitinggqapparatue for a-a potty.pe:,oi1; burner; :.the a com ration inctudixI-Ie: a

substantially horizontal r- 'aglotttube --sec,urab1e at 5,;

its inner-.'end:t0; the reservoir vOf: a:;-pot:.type:: oil. burner; a tube end. plate closing the outereenjd of-grthetube lam-eansrtot introduce :oil: into ;.the;pi1ot tubei; inner" and outerpartitions in '"thempiloti d'jace-n trtoandrrextending 15 tube,;a.- defini-ng-g;a pilot; ch :mber: shorter-than gthe pilot :tube adjacent the-winner? end-:Of etheetub a the; partitions;-:eaehmatings-a; port; adjacent ,=t0

section extending into the pilot chamber. a

.-9;- Apparatus: as claimed. in: claim 8 whe1:ein the; inner end 5 .of v the Fair-tube 1s 'substantially-vclosed and the air-ports:thfi feintare fogemed to;

direct air issuin therefrom:vsubstantially mngential to the wall of @the pilot chamber.

References Cited -:in the .,fi1e of )this patent UNITED STATES} PATENTS J 

